Decretals, etc
MLA
Pseudo-Isidore. Decretals, Etc. 0AD. https://collections.library.yale.edu/catalog/2017751.
APA, 6th edition
P.-I. (0 C.E.). Decretals, etc [Manuscripts, Medieval France 9th century, Medieval and Renaissance Manuscripts in Beinecke Library]. https://collections.library.yale.edu/catalog/2017751.